Lights for stage and production operations are often heavy and awkward. These lights are intended to be remotely controlled, and also to project a high intensity light. The lights often include special bulbs and ballasts. The lights are mountable on trusses, but often very difficult to handle. Many devices, for example, require two men to carry them.
The lights are often rented, and after the rental is completed, they must be tested to be readied for the next rental. This means testing the lights.